Polyalkylene oxides stabilized with a bisphenol and a thioether



United States Patent Ofilice 3,365,419 POLYALKYLENE OXIDES STABILIZEDWITH A BISPHENOL AND A THIOETHER Claus Heuck, Hofheim, Taunus, and OttoMauz,

Frankfurt am Main, Germany, assignors to Farbwerke HoechstAktiengesellschaft vormals Meister Lucius & Bruning, Frankfurt am Main,Germany, a corporation of Germany No Drawing. Filed Aug. 18, 1964, Ser.No. 390,470 Claims priority, application Germany, Aug. 20, 1963, F40,535 8 Claims. (Cl. 260-4585) ABSTRACT OF THE DISCLOSURE Thestabilization of polyalkylene oxides with a mixture The presentinvention relates to a process for stabilizing polyalkylene oxides withthe aid of a mixture of phenols and thioethers.

It is known that homo and copolymers of alkylene oxides are more or lessliable to degradation at higher temperatures under the action of oxygenand light like all polyethers and that they must be stabilized prior tobeing processed or used. It has already been proposed to use aromaticamines or phenols as stabilizers for propylene oxide. However, when thepolymers are processed at a temperature above 100 C. the saidstabilizers are little effective and they do not prevent the polymerfrom being decomposed at a higher temperature, for example at 110 C.

It has now been found a process for stabilizing polyalkylene oxidesusing a stabilizer mixture consisting of (I) a phenol of the generalformula:

3,365,419 Patented Jan. 23, 1968 in which R stands fora hydrogen atom,an aliphatic alkyl radical with 1 to 17 carbon atoms, a phenyl radicalwhich may still contain a hydroxyl group and alkyl group or the groupingR and R stand for a hydrogen atom, an aliphatic alkyl group with up to18 carbon atoms; R represents a methyl group, ethyl group or tertiarybutyl group, R is a branched alkyl radical with up to 12 carbon atoms; Rstands for a hydrogen atom, an alkyl group with up to 12 carbon atoms; Rrepresents an alkyl radical with 1 to 18 carbon atoms and It means zeroor a whole number in the range of l to 4; and (II) an aliphaticthioether having the general formula R S -R in which R represents analkyl radical With 8 to 20 carbon atoms or the group (CH -COOR R beingan alkyl radical with 8 to 20 carbon atoms and x a whole number of 1 to4, and It means a whole number in the range of 1 to 4. In the stabilizermixture the ratio of component I to component II is in the range of from1:5 to S: 1.

From among the phenolic components to be used in the process of theinvention there are mentioned by way of example: his2-hydroxy-3-methyl-S-isooctylphenyl) -met'hane, 4,4 bis(4 hydroxyphenyl)pentanoic acid dodecyl ester, 3,3-bis(4-hydroxy-3 methylphenyl) butanoicacid dodecyl ester, condensation products of 3-methy1-6-tert.butylphenol with croton-aldehyde, butyraldehyde, salicyclic aldehyde,octylsalicyclic aldehyde or acrolein.

The aforesaid condensation products are prepared in known manner, forexample as described in the Journal of the American Chemical Society,volume 63, page 1731 (1941) or page 1422 (1939).

As organic sulfur compounds there may be used: thiodiglycolic aciddodecyl ester, thio-dipropionic acid dodecyl ester,di(octadecyl)sulfide, di(octadecyl)disulfide, di(octadecyl trisulfide,or di (octadecyl) tetrasulfide.

In order to obtain a good stabilizing elfect the stabilizer mixtures arepreferably used in an amount of 0.3 to 3%, calculated on the weight ofthe polymerization product, either as solid or as solution. Thestabilizer mixture is advantageously added in the course of theprocessing of the polymerization product directly 'after thepolymerization process. It is likewise possible, however, to add thestabilizer to the solid polymer after processing. In this case mixingcan be accomplished, advantageously with the exclusion of air, byrolling on a multiple roll mill as used, for example, in rubberindustries or in a suitable kneader or extruder. With the stabilizermixtures of the invention there can be stabilized homoand copolymers ofalkylene oxides. The said homoand copolymers are produced bypolymerizing saturated alkylene oxides, for example ethylene oxide,propylene oxide and isobutylene oxide, substituted epoxides such asepichlorohydrin, perfluoropropylene oxide and 1-chloro-3,4-epoxybutane,cycloaliphatic epoxides such as cyclohexene oxide, epoxy ethers such asmethyland phenylglycidyl ethers, or by copolymerizing unsaturated andsaturated epoxides, for example allylglycidyl ether, glycidyl acrylate,vinylcyclohexane monoinvention without the addition of sulfur compounds.The compounds used in Experiments 4 and 5 are the stabilizers disclosedin US. 'Patent 2,706,189, page 2, column 3. The comparative experimentsshow that the sole use of the phenols (Experiments 15) has a littlestabilizing epoxide, cyclohexene oxide, butadiene monoxide and 1,2-efiect whereas the sole use of the thio compounds(Exepoxy-cyclooctene-(S), in the presence of known ionic periments 68)is practically without stabilizing effect. catalysts. Especially goodresults can be obtained with co- As polymer a polymer of propylene oxidewas used and polymers of saturated and unsaturated alkylene oxides thefilms were heated at 110 C.

TABLE 1 Experiment Gone. 1 red. 1 red. 1; red. N o. Stabilizer percentby initial after after Weight value 24 hrs. 48 hrs.

1 Bis(2-hydroxy-3-methyl-5-isooetylphenyl)- 1 13.85 2.71 1.15

methane-(1). 2 3,3-bis(4-hydroxy-3-methylphenyl) butanoic 1 14.00 3.151.97

acid dodecyl es r. 3 3-methyl-6-tert.butylphenol/crotonaldehyde 1 13.953.95 2.71

condensation product. 2,6di-tert.butyl-p-cresol 1 13. 71 1. 21 0.13 Bis(4-hydroxyphenyD-propane-(2) 1 13. 62 1. 61 0. 41 'lhio-dipropionicacid dodeeyl ester. 1 13. 88 0. 97 Di(n-octadeeyl) disulfide 1 13. 970.98 8 Di(n-octadecyl) trisultidc 1 13. 79 0.76 0.01

when the stabilization is carried out in the uncrosslinked Example 2state, i.e. directly after polymerization. The stabilized polymersobtained are crystalline, amorphous or rubberlike. The stabilizingaction of the compounds used according to the invention has been testedin the following manner:

The stabilizer dissolved in benzene was added to the benzenic solutionof the polyalkylene oxide or copolymer. A film was made from thethoroughly mixed solution and the film was heated in a drying cabinet at110 C. with the admission of air. Samples were taken every 24 hours, abenzenic solution of 0.1% strength was prepared and the reduced specificviscosity was measured at 25 C. The drop of the reduced specificviscosity is the measurement for the oxidative degradation of thepolymer.

tion, but they are not intended to limit it thereto.

The following examples serve to illustrate the inven- Example 1 In Table1 comparative experiments 1 to 3 show the results obtained with phenolsto be used according to the The polymer used was a polymer of propyleneoxide. The =film was stabilized with 0.5% by weight of a phenol compoundand 0.5 by weight of a thio compound. The films were heated at C. Theresults obtained are recited in Table 2. Experiments 10-14 show that thecombination of relatively little active phenol compounds withpractically uneffective sulfur compounds has an excellent stabilizingefiect. An unstabilized polymer film is completely decomposed afterhaving been heated at 110 C. for 3 hours.

Example 3 A copolymer of propylene oxide with 1,2-epoxy-cyclooctene-(S)was used. The stabilizer combination was added in an amount of 1% byweight. The films were heated at 110 C. The results obtained aresummarized in Table 3.

Example 4 A copolymer of propylene oxide and allylglycidyl ether wasstabilized. The film was heated at a temperature of 110 C. The resultsobtained are listed in Table 4.

TABLE 2 Experi- Cone. percent 1; red. n red. red. red. (1 ment No.Stabilizer by weight initial after after atter itf er value 24 hours 6days 10 days 20 days 10 3-methyl-fi-tert.butylphenol/erotonaldehyde 0.5

condensation product. 11.3 8.2 6.5 3 3 2 1 Thio-dipropionic acid dedecylester 0.5 l

11 3-metlliyl-fi-tert.butglphenol/butyraldehyde 0.5

con cnsa ion pro uct. 11.7 8.5 Thio-dipropionic acid dodecyl ester 0. 5i 6 3 4' 2 3' 0 12 3-n1l(:1t;l;1yl(-i6-tert.butylphenol/oetylsalicylic0.5

a e y e. 10.9 Di(n-octadeeyl)disulfide 0.5 8 7 8-0 6'9 4'3 13Bis(2-hydroxy-3-methyl-5-isonony1phenyl)- 0.6

dimethyhnethane. 11.6 8.1 7 5 5 7 2 8 Thio-dipropionie acid dodecylester 0.5 i

14 Without stabilizer (comparative experiment) 11.2 after 3 hours 1,red. 0.10

TABLE 3 Cone. n red. 1; red. 1 red. 7 red. 1; red. 1 red. 1, red. 1 red.1; red. 1, red. 1; red. 1, red. Experi- Stabihzer percent initial afterafter alter after after after after after after after after ment No. byvalue 3 24 48 6 8 10 14 17 20 22 24 weight hours hours hours days daysdays days days days days days 15 Without stabilizer 13.85 23 16bis(2-hydroxy3- 0.5

methyl-fi-isooctylahenyD-methane- 13.86 9. 43 7.69 6.25 5.79 5.40 5.074. 54 4.22 3.35 3.92 Thio dipropionic acid 0.

dodecyl ester.

17 3,3-bis(4-hydroxy-3- 0.5

methylphenyl)- butanoic acid 13.95 8.13 8.02 6.40 5.66 4.70 4.25 3.96 3.93 3.40 3.03 dodecyl ester. Di(n-octadecy1)- 0. 5

disulfide.

18 3-methy1-6-tert.buty1- 0.5

phenol/crotonalde hydde Condensation 14.15 10.55 10.23 8.31 8.25 7.867.16 6.42 6.17 2.86 2.75 pro uc Thio-dipropionic acid 0. 5

dodecyl ester.

19 3-methyl-6-tert.butyl- 0.5

pheuol/crotonaldehyde condensation 13. 85 9. 55 8. 21 6. 39 6. 30 5. 875. 46 5. 27 4. 30 4.11 3. 98 product. Di(n-octadecyl)- 0. 5

disulflde.

20 Bis(2-hydroxy-3- 0.5

methyl-fi-isooctylphenyD-dimethyl- 13.85 8.60 8.21 5.85 5.35 3.90 2.902.30 2.25 1.80 1.71 methane-(1). Di(n-octadecyl)- 0. 5

trisulflde.

TABLE 4 Experi- Gone. 1, red. 1 red. 1 red. 1; red. 1; red. 1; red. 1red. ment No. Stabilizer percent by initial after after after afterafter after weight value 24 hours 48 hours 6 days days 14 days days 21B-methyl-fi-tert.butylphenol/acrolein 0.5

Thio-dipropionic acid dodecyl ester. 0.5 i

22 3-methyl-6-tert.butylphenol/he tanol. 0.5

Dimmtadecyl) msulfidemuiln M 13.2 10.5 9.7 7.9 6.1 5.4 4.9

23 4,4-bis(4-hydroxyphenyl)-pentanoic acid do- 0.5

decyl ester. 13. 2 9.8 8. 6 6. 8 5. 1 4. 6 3. 2 Di(n-octadecyl)disulfide 0. a

We claim: atoms, phenyl, phenyl containing a hydroxyl and an alkyl 1. Apolyalkylene oxide polymer stabilized by from group, the group 0.3 to3.0 percent by weight of a mixture consisting of ('I) a phenol selectedfrom the group cons-1st1ng of a phenol of the formula (a) CH; CH:

(CH3)3C HO- (|3H OH 5 I 0 R I OH C(CHS mom): and the rou a phenol of theformula (b) g p CHCHOH on R on 1 CH3 R (|3- R R2 (C a)aC l OH R4 R4 anda phenol of the fo mula R and R are members selected from the groupconsist- OHE ing of hydrogen and aliphatic alkyl having up to 18 car- R5bon atoms, R is a member selected from the group con- Q I sisting ofmethyl, ethyl and tertbutyl, R stands for 110 011 branched alkyl havingup to 12 carbon atoms, R is a member selected from the group consistingof hydrogen and alkyl havmg up to 12 carbon atoms, R stands for COO.Ru

alkyl having up to 18 carbon atoms and n is a whole wherein -R is amember selected from the group consistnumber in the range of 0 to 4, and(II) an aliphatic mg of hydrogen, aliphatic alkyl having up to 17 carbonthioether of the formula R S R in which R is a member selected from thegroup consisting of alkyl having 8 to 20 carbon atoms and the grouping Rbeing alkyl having 8 to 20 carbon atoms and x equaling 1 to 4, and itstands for a number in the range of 1 to 4, components I and 11 beingpresent in a ratio of 1:5 to 5:1.

2. The polymer of claim 1 wherein the phenol has formula a.

3. The polymer of claim 1 wherein the phenol has formula b.

4. The polymer of claim 1 wherein the phenol has formula 0.

5. The polymer according to claim 1, wherein the phenol is acondensation product of 3-methyl-6-tert.butyl phenol and butyraldehydeand the thioether is thio-dipropionic acid dodecyl ester.

6. The polymer according to claim 1 wherein the 8 phenol is3,3-bis(4-hydroxy 3 methylphenyl) butanoic acid dodecyl ester and thethioether is di(n-octadecyl)disulfide.

7. The polymer according to claim 1 wherein the phenol is a condensationproduct of 3-methyl-6-tert.butyl phenol and crotonaldehyde and thethioether is di(n-octadecy1)disulfide.

8. The polymer according to claim 1 wherein the phenol is bis(2hydroXy-3-methyl S isooctylphenyl)- methane-(1) and the thioether isthio-dipropionic acid dodecyl ester.

References Cited UNITED STATES PATENTS 3,204,014 8/1965 Green 260-8953,277,044 10/1966 Weissermel et al. 26045.8

DONALD E. CZAJA, Primary Examiner.

V. P. HOKE, Assistant Examiner.

